PROJECT SUMMARY/ABSTRACT More than 10 million Americans have osteoporosis, and an additional 36 million have low bone density, or osteopenia. Osteoporosis represents a major health problem, resulting in substantial increases in national health care costs. Current methods to detect osteoporosis rely upon ionizing techniques such as Dual-energy X-ray Absorptiometry (DXA) and Quantitative Computed Tomography (QCT). A pilot study conducted by our collaborators indicated a possible correlation between readings of an array of passive on-skin 900 MHz Radio Frequency Identification (RFID) tags surrounding a wrist and an osteoporotic bone condition established via DXA measurements. We therefore hypothesize that a professional acquisition testbed, using this novel low- cost non-ionizing technique, can detect osteoporosis. Specific Aim 1 (PHASE I): Design and construct a novel on-body passive-RFID antenna array testbed for highly-sensitive and repeatable measurements of wrist bone signature. In contrast to a common microwave imaging setup with multiple antennas, the use of an RFID array instead of one tag is solely intended for more accurate and stable reading of the single parameter ? the average received power through the wrist ? given different anatomical and physiological conditions. Specific Aim 2 (PHASE I): Determine the sensitivity of the bone signature measured by the testbed for differentiating between normal and osteoporotic bones at wrists using in-vivo pilot studies. The ultimate technical goal of Phase I (and partially of Phase II) is to achieve a sufficient measurement accuracy of the testbed, i.e. guarantee the average received power variability for each wrist of less than 0.5 dB (factor of 1.1) for at least 75% of tested wrists. This threshold value will make it possible to extract the desired signal from the surrounding noise and detect the osteoporosis-related power variation, which is expected to be in the range 2-5 dB (factor of 1.6-3.2). Specific Aim 1 (PHASE II): Finalize the major antenna concepts and protect the RFID antenna bone density testbed by filing at least one full-scale patent with the special emphasis on the unique reader/tag antenna array design, and on possible extensions. Convert the RFID antenna testbed to a semi-commercial product. One feature of the present study will be a novel and unique on-body antenna design, which will allow us to realize a highly-sensitive detection method in practice. Specific Aim 2 (PHASE II): Calibrate the finalized RFID antenna testbed by performing and processing a representative in-vivo study and delivering a final detection protocol. Finalize and perform premarket regulatory submission of the developed wrist sensing RFID device to the U.S. Department of Health and Human Services, Food and Drug Administration, Center for Devices and Radiological Health. We hypothesize that the newly designed testbed will differentiate between normal, osteopenic and osteoporotic bone sufficiently to warrant a premarket regulatory FDA submission related to a specific Class III device. Specific Aim 3 (PHASE II): Approach the production stage by either teaming up with a larger medical company or a 3rd party manufacturer. Potential candidates include Biotronik, Boston Scientific, St. Jude Medical, Inc. and Medtronic, Inc.